1. Field of the Invention
The present invention relates to an audio processing apparatus.
2. Description of the Related Art
An imaging apparatus capable of recording sound with a captured moving image is known as the conventional audio processing apparatus.
In the imaging apparatus, a problem that noise generated according to driving of an optical system is recorded as sound is raised and, thus, various noise reduction techniques relating to the problem are developed as discussed in Japanese Patent Application Laid-Open No. 2006-203376. In Japanese Patent Application Laid-Open No. 2006-203376, a technique for complementing sound generated in a noise generating section by using sound in the section immediately before driving a motor, in a case where an iris motor or a shutter motor of the imaging apparatus is driven, is discussed.
Japanese Patent Application Laid-Open No. 2008-053802 discusses a concealing method for concealing a head retraction noise of a hard disk drive. More specifically, an audio signal of a portion where the head retraction noise of the hard disk drive has been generated is generated based on signals before and after the audio signal to conceal the head retraction noise.
In the “International Telecommunication Union-Telecommunication Standardization Sector (ITU-T) Recommendation G. 711-Appendix I”, a packet loss concealing method is disclosed in an audio transmission relating to a transmission and demodulation of sound. More specifically, a signal of the portion where the packet has been lost is generated by predicting the signal of the portion based on the signal before the packet has been lost. Further, when a packet is normally acquired again, a correction is made with a prediction such that a signal in a packet before the normal packet can be smoothly continued to the normal packet.
However, in a case where a noise reduction is performed by using the technique discussed in Japanese Patent Application Laid-Open No. 2006-203376, for example, if the iris motor and the shutter motor are sequentially driven, a noise of the iris motor may be contained in, for example, the sound for complementing a sound of a section during which the shutter motor is driven. In the above case, another noise is contained in the noise section, resulting in degradation of a noise reduction effect.